•
Mac: The
classic Mac OS supported system extensions known generally as FKEYS which could be installed in the System file and could be accessed with a
Command-Shift-(number) keystroke combination (Command-Shift-3 was the
screen capture function included with the system, and was installed as an FKEY); however, early Macintosh keyboards did not support numbered function keys in the normal sense. Since the introduction of the
Apple Extended Keyboard with the Macintosh II, however, keyboards with function keys have been available, though they did not become standard until the mid-1990s. They have not traditionally been a major part of the Mac user interface, however, and are generally only used on cross-platform programs. According to the
Macintosh Human Interface Guidelines, they are reserved for customization by the user. Current Mac keyboards include specialized function keys for controlling sound volume. The most recent Mac keyboards include 19 function keys, but keys – and – by default control features such as volume, media control, and
Exposé. Former keyboards and Apple Keyboard with numeric keypad have the – keys. •
Mac laptops: Function keys were not standard on Apple notebook hardware until the introduction of the PowerBook 5300 and the PowerBook 190. For the most part, Mac laptops have keys through , with pre-defined actions for some, including controlling sound volume and screen brightness. •
Apricot PC/Xi: six unlabelled keys, each with an
LED beside it which illuminates when the key can be used; above the keys is a
liquid crystal display—the 'microscreen'—that is used by programs to display the action performed by the key. •
Atari 8-bit computers: four dedicated keys (Reset, Option, Select, Start) at the right hand side or on the top of the keyboard; the XL models also had a
Help key. Atari 1200XL has four additional keys labeled through with pre-defined actions, mainly related to cursor movement. •
Atari ST: ten
parallelogram-shaped keys in a horizontal row across the top of the keyboard, inset into the keyboard frame instead of popping up like normal keys. •
BBC Micro: red/orange keys
F0 to
F9 in a horizontal row above the number keys on top of the computer/keyboard. The break, arrow, and copy keys could function as –. The case included a transparent plastic strip above them to hold a function key reference card. •
Coleco Adam: six dark brown keys in a horizontal row above the number keys, labeled with Roman numerals I–VI. •
VIC-20 and
Commodore 64: / to / in a vertical row of four keys descending on the computer/keyboard's right hand side, odd-numbered functions accessed unshifted, even-numbered shifted; orange, beige/brown, or grey key color, depending on VIC/64 model/revision. •
Commodore 128: essentially same as VIC-20/C64, but with (grey) function keys placed in a horizontal row above the numeric keypad right of the main QWERTY-keyboard; also had
Help key. •
Commodore Amiga: ten keys arranged in a row of two five-key groups across the top of the keyboard (flush with the ordinary keyboard top row); function keys are 1½ times the width of ordinary keys. Like the Commodore 128, this also had a
Help key. •
Graphing calculators, particularly those from
Texas Instruments,
Hewlett-Packard and
Casio, usually include a row of function keys with various preassigned functions (on a standard hand-held calculator, these would be the top row of buttons under the screen). On low-end models such as the
TI-83-series, these function mainly as an extension of the main keyboard, but on high-end calculators the functions change with the mode, sometimes acting as menu navigation keys as well. •
HP 2640 series terminals (1975): first known instance—late 1970s—of
screen-labeled function keys (where keys are placed in proximity or mapped to labels on CRT or LCD screen). •
HP 9830: – on two rows of four in upper left with paper template label. An early use of function keys (1972). •
IBM 3270: probably the origin of function keys on keyboards, circa 1972. On this mainframe keyboard early models had 12 function keys in a 3×4 matrix at the right of the keyboard; later that changed to a numeric keypad, and the function keys moved to the top of the keyboard, and increased to 24 keys in two rows. •
IBM 5250: early models frequently had a "cmd" modifier key, by which the numeric row keys emulate function keys; later models have either 12 function keys in groups of 4 (with shifted keys acting as –), or 24 in two rows. These keys, along with "Enter", "Help", and several others, generate "AID codes", informing the host computer that user-entered data is ready to be read. •
IBM PC AT and PS/2 keyboard: to usually in three 4-key groups across the top of the keyboard. The original IBM PC and PC XT keyboards had function keys through , in two adjacent vertical columns on the left hand side; |, |, ..., |, descending. Some IBM compatible keyboards, e.g., the
Northgate OmniKey/102, also featured function keys on the left, which on examples with swapped left and keys, facilitate fingers of a single hand simultaneously striking modifier key(s) and function keys swiftly and comfortably by touch even by those with small hands. Many modern PC keyboards also include specialized keys for multimedia and operating system functions. •
MCK-142 Pro: two sets of function keys: – at the left side of the keyboard and additionally 24 user programmable PF keys located above QWERTY keys. •
NEC PC-8000 Series (1979): five function keys at the top of the keyboard, along with a numeric keypad on the right-hand side of the keyboard. •
Sharp MZ-700: blue keys to in a horizontal row across the top left side of the keyboard, the keys are vertically half the size of ordinary keys and twice the width; there is also a dedicated "slot" for changeable key legend overlays (paper/plastic) above the function key row. •
VT100 terminals: four function keys (PF1 - PF4) above the
numeric keypad. ==Action on various programs and operating systems==